1. Field of the Invention
This invention relates to nozzles and caps used on dispensing tubes for caulking material, sealant, adhesives and the like.
2. Description of Related Art
Caulking and sealant material is commonly sold in compressible tubes with dispensing nozzles for accurate placement of the material. The tubes are available in two general forms. The first comprises a hand squeezable tube having a threaded outlet on one end and the other end is sealed by sealing the two halves of the cylindrical wall together to form a flat, leak-proof connection. A conical, hollow, removable nozzle is screwed on the threaded outlet. The nozzle contains, at its distal end, an aperture for dispensing the material. This type of tube usually contains a relatively small quantity of material for small jobs or repairs. For larger jobs, the tube generally has a nozzle mounted on a circular plate which seals one end of the tube. The other end of the tube contains a movable, circular seal placed within the cylindrical wall of the tube. The tube is placed in a caulking gun which has a piston which engages the circular seal. Means are provided on the caulking gun for gradually forcing the piston against the seal. As the seal is forced into the tube, the material contained therein is expelled through the nozzle aperture.
In either case, the nozzle is hollow and generally conical in shape with the widest diameter located near the tube and the smallest diameter at the distal end of the nozzle. The nozzle can be cut off anywhere between the tube end and the distal end thus fixing the diameter of the nozzle exit aperture and therefore the diameter of the caulking material bead dispensed by the tube-nozzle combination.
These arrangements work fine when all of the material in the tube is dispensed in the course of the job. However, if only a portion of the material is dispensed on a particular job, the sealant or caulking material usually hardens in the nozzle thus plugging the aperture and wasting a significant quantity of the material. Prior to using the tube again, effort and time must be expended to clear the nozzle.
In the case of the removable nozzle, the nozzle must be unscrewed from the tube and an instrument inserted in the aperture of the nozzle to force the hardened plug out the larger diameter end of the nozzle. If the hardened material within the nozzle is an adhesive, this task can be very difficult often ending in the destruction of the nozzle. In the case of the fixed nozzle, the problem is more difficult. Since the nozzle cannot be removed, the dried plug must be extracted from the nozzle aperture. Since the nozzle is conical with its smallest diameter at the aperture, a sharp instrument must be inserted in the aperture to cut up the solidified plug so the pieces can be removed from the aperture.
One approach to resolving this problem is exemplified by U.S. Pat. No. 4,878,599 issued to John M. Greenway on Nov. 7, 1989. This patent discloses a generally conical shaped nozzle made up from a plurality of cylinders of decreasing diameters. This design facilitates the removal of the dried plug because, provided the dried plug is located in only one of the cylindrical sections, its diameter is constant and it can easily be pried or forced out of the nozzle aperture. However, if the dried plug extends for a sufficient length to include two cylindrical sections of the nozzle, the step change in plug diameter makes it even more difficult to remove than the plug formed in an evenly taper nozzle.
A more practical and effective solution to this problem is to provide a re-sealable nozzle cap assembly which prevents drying of the caulking or sealing material while still providing an adjustable nozzle aperture outlet diameter for controlling the size of the dispensed bead.